Step 1

Pat shrimp dry with paper towels; toss with 1/2 teaspoon salt and 1/4 teaspoon pepper. In a small bowl, whisk together cornstarch, oyster sauce, and 3/4 cup water.

Step 2

Heat a large skillet (preferably cast-iron) over high. Swirl in oil, then add shrimp in a single layer; cook, undisturbed, 1 minute. Continue to cook, stirring occasionally, until almost cooked through, 1 to 2 minutes more. Add celery, garlic, ginger, and red-pepper flakes; cook, still stirring, 1 minute. Add cornstarch mixture; stir until sauce thickens and coats shrimp and vegetables, about 1 minute more. Stir in cashews; serve over rice, topped with celery leaves and more red-pepper flakes.